Mitochondrial Biogenesis and Skeletal Muscle Metabolic Adaptation to Endurance Training in Nigerian Elite Female Athletes: Molecular and Physiological Mechanisms

Background: Endurance training induces mitochondrial biogenesis in skeletal muscle through peroxisome proliferator-activated receptor-gamma coactivator-1 alpha signalling, improving oxidative metabolism and fatigue resistance. Female athlete physiology differs from male counterparts due to oestrogen-mediated modulation of substrate utilisation and mitochondrial function. Molecular characterisation of training-induced mitochondrial adaptations in African female endurance athletes has never been reported. Objectives: This study aims to characterise training-induced changes in skeletal muscle mitochondrial biogenesis markers, including peroxisome proliferator-activated receptor-gamma coactivator-1 alpha, mitofusin-2, and citrate synthase activity, alongside maximal fat oxidation rates and peak oxygen uptake, in elite Nigerian female long-distance runners and compare molecular profiles with age-matched sedentary controls. Methods: Twenty-five elite female runners from the Nigerian Athletics Federation programme and twenty-five sedentary controls will be recruited. Percutaneous needle biopsies of the vastus lateralis will be obtained at rest and four hours after a standardised exhaustive treadmill bout. Protein expression will be quantified by western blot. Mitochondrial enzyme activities will be measured spectrophotometrically. Maximal fat oxidation will be determined by indirect calorimetry. Mixed-model ANOVA will compare groups and time points. Expected Outcomes: Trained athletes are anticipated to exhibit 2.5- to 4-fold greater mitochondrial biogenesis markers at rest and an amplified post-exercise peroxisome proliferator-activated receptor-gamma coactivator-1 alpha response compared to controls. Conclusion: This study will produce the first molecular exercise physiology data from elite Nigerian female athletes. Keywords: mitochondrial biogenesis, endurance training, female athletes, peroxisome proliferator-activated receptor-gamma coactivator-1 alpha, skeletal muscle.